Freestone Streams

A freestone stream’s water source is either snowmelt or rainfall,
so they rely upon precipitation for their flow volume. Freestones
generally have steep gradients characterized by areas of rapid and fast
currents. They are usually sited in canyon areas.

A freestone stream’s volume crests in early summer while its flow
diminishes in the fall and winter. The stark contrast between late
springtime and winter flows can be surprising. A once productive summer
side-channel may be bone dry in the winter. Springtime flows may be high
and muddy yet run low and clear the rest of the season. High flows
commonly scour stream channels. Rooted aquatic plants have difficulty
surviving the seasonal heavy flows. Stream channels can change from one
year to the next. Some scouring may be beneficial if it washes away excess
silt accumulated in the rocky, gravelly, riffled sections. Freestones are
distinguished by few rooted aquatic plants and by an abundance of gravel
and rocks.

Aquatic insects require plants to exist. Riffles support sheltered areas
for limited plant growth. Aquatic insects live and feed in the riffled
areas where the enhanced surface areas between the rocks support plant
habitat. Hence, the riffles provide the freestone stream with its
abundance of

aquatic insects for the fish to forage.

A freestone stream’s pH is usually slightly acidic. In times of
excess acid, plants, insects, and fish may perish. The snow pack at a
stream’s source can accumulate acidic precipitation. This is
concentrated into the bottom layer of snow. As this bottom layer melts,
the sudden release of acid can be devastating to its downstream
environment.

A freestone stream is more readily influenced by the ambient air
temperature, resulting in wide temperature fluctuations. Winter cold can
cause a stream to run close to freezing while summer heat can cause it to
exceed 70°F. This wide variation shortens a fish’s growing
season which occurs when the water temperature is between 55-65 degrees.
The lowered winter and late summer diminished water volume is more easily
influenced by ambient temperature changes. Conditions of bottom ice along
with an ice lid surface can induce winter kill of both insects and fish.
Likewise, summer die-offs occur due to excessively warm temperatures which
forfeit water’s ability to hold sufficient oxygen.

The productive freestone streams are restricted to ideal altitudes and
latitudes where seasonal temperatures are favorable for aquatic life.

As a general rule, the freestone stream’s growing season is much
shorter than a spring creek’s, because freestones are more prone to
wide temperature fluctuations.

In summary, freestones are subject to times of plenty and to times of
drought. They are not as rich in food resources as spring creeks. Their
grace is that freestones are wider, longer, and more numerous than spring
creeks. Nonetheless, freestones are less crowded than spring creeks. Since
freestones have fewer fish than a spring creek, an angler must cover more
water in search of fish.